Ultimately, Karunasena hopes her findings can help humans. Some scientists have suspected
for decades the same bacteria - mycobacterium avium subspecies paratuberculosis -
that causes Johne's in livestock causes an irritable bowel syndrome, called Crohn's
disease, in humans.

"No one has found the link yet," cautions Karunasena.

Some 500,000 Americans have Crohn's.

The same germ believed to trigger the disease is often the first to

overcome AIDS patients' faltering immune systems.

Yet little is known about how Crohn's develops in humans or how humans contract mycobacterium
avium subspecies paratuberculosis. The germ can be found virtually anywhere - in the
soil, the water, even in hospitals, Karunasena said.

Proper pasteurization of milk products and proper cooking of beef products kills the
germ, research shows.

"Predisposing assumptions on (these) products, alone, would be bad science, although
it would be an appropriate starting point to investigate," Karunasena, 31, told The
Avalanche-Journal.

Her starting point, however, revolves around bovines - animals the young researcher
never imagined she'd study.

Karunasena is working under Mindy Brashears. Brashears, a Tech associate professor,
discovered a cocktail of good and bad bacteria that kills food-borne illnesses such
as Salmonella and E.Coli in processed beef and poultry. The FDA endorsed the mixture in 2005.

The team has found another antidote - Johne's symptoms are suppressed in cattle that
are fed dietary supplements that contain beneficial bacteria and yeasts. In grocery
stores, these probiotics are found in foods such as yogurt and cheese.

Dairy cows that eat the supplements produce more milk and deposit more fat in that
milk, which is a sign of good health, Karunasena said.

"But no one knows why that is," she said.

This is where some 300 mice will play a role.

Karunasena's team will infect them with Johne's, feed them probiotics and monitor
how it effects their health. The ultimate goal is to determine whether probiotics
can prevent the onset of Johne's.

On U.S. farms and ranches, Johne's reach is relatively unknown. Testing of American
cattle herds isn't mandatory because there's no proven human health link, said Andy
Schwartz, a veterinarian with the Texas Voluntary Johne's Disease Program for Cattle.

Studies show dairy cattle are more prone to the disease than beef cattle. Some dairies
voluntarily test their herds - roughly 26 percent of dairy operations, according to
a USDA study conducted in 2002 and 2003 and released in 2005.

The latest USDA study, which will be released in April, shows the Johne's-triggering
germ was present at about 68 percent of dairies that tested for it in 2007, said Rachel
Iadicicco, a USDA spokeswoman. But cattle that test positive for the germ don't always
develop the disease, and incubation periods can be as long as four years.

"This is really the dilemma. How do you stop the disease when you don't know whether
an animal positive for the organism in their system will develop it or not?" Karunasena
said.

Regionally, Johne's is considered an economic risk but not an eminent threat, local
veterinarians said. Nationally, it's more prevalent in northern states, such as Wisconsin
and Minnesota. In this state, it's more prevalent in East Texas. In West Texas, cattle
have more room to roam and an arid climate to keep bacteria at bay, veterinarians
said.

If the disease does infect a herd, it slices profits. An infected cow's milk production
slows to a trickle.

"The way agriculture is today you have to save every dime you can. You just can't
afford (Johne's) in a cow herd," said Louis Farr, a Lubbock County veterinarian

In humans, finding a shield against Crohn's disease is a complex, distant goal, Karunasena
said. Our food supply, though, is a piece of the puzzle.

"If we keep our animals healthy, it's only going to have benefits for our health,
too," she said.